January 18, 2021

Good Graphics Clarify Technical Attributes of Power Process

3 min read
When I read a technical article, I often find that many authors have forgotten the...

When I read a technical article, I often find that many authors have forgotten the rule that “a picture is worth 1,000 words.” Rather than using s simple image to provide context and clarify the situation before they delve into details, they often spend a lot of words describing the situation while neglecting to “set the stage” for the audience. Instead, they go through their various points in an organized linear fashion — which makes sense — but without providing a visual and, thus, a memorable foundation.

Please note than is not just an issue for technical material, nor is it the usual (false) theme that “engineers can’t write;” in fact, it’s often worse in general for non-fiction. For example, the otherwise fascinating writer John McPhee has what I’ll characterize as a writing style honed at The New Yorker magazine, which takes an almost perverse delight in using pages and pages to describe anything from geological formations to cargo-ship technology by using thousands of words when a photo or drawing would make more sense.

Then there’s Dava Sobel’s surprising 1995 best-seller, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time” about John Harrison, an 18th century clockmaker who created the first clock sufficiently accurate to be used to determine longitude at sea — a  monumentally important development in navigation. She, too, describes some of Harrison’s brilliant mechanisms and error-compensating techniques in hundreds and hundreds of words, when a straightforward drawing would have been much better. It’s almost as if these authors simply love to hear themselves. (Perhaps because there were many complaints about the graphical deficiencies in the book, as noted in this review, that the author subsequentially came out with the follow-on volume The Illustrated Longitude, which had the full original text but 178 illustrations!)

A good graphic can tell a story and establish a baseline for discussion. I saw the chart of Figure 1 in a recent Texas Instruments blog post, Automotive GaN FETs engineered for high frequency and robustness in HEV/EVs. It nicely summarizes the perspective of the author on the important topic of frequency versus power-handling capability for various basic process technologies.

Fig. 1: This chart crisply compares and contrast the present state of capabilities of power semiconductor technologies across their two top parameters. (Image source: Texas Instruments)

Another clear chart shows an assessment of the relative power capabilities of various RF power-device technologies, again versus frequency, Figure 2.

Fig. 2: This chart provides a similar comparison, but for RF power devices. (Image source: Fairview Microwave via Microwave Product Digest)

Of course, others may have somewhat different perspectives, and that’s OK. These charts at least provide some frame of reference to start a discussion. The boundaries are not static, either, as it’s likely that the boundaries will shift as technology changes occur.

Anther chart that vividly compares process technologies uses a pentagon to show the differences among three standard technologies across five parameters, along with the relative size of these differences, Figure 3.

Fig. 3: By using a polygon-like arrangement, this chart nicely highlights the relative differences between silicon, silicon carbide, and gallium nitride technologies with respect to five key parameters. (Image source: Researchgate)

I’ve read and attended lots of PowerPoint presentations where the graphics have ranged from dreadful to excellent. Regardless of your topic or focus, I’d recommend that you check out the classic book by Prof. Edward Tufte, The Visual Display of Quantitative Information. Even if you don’t have an immediate need, the book is visually delightful and thought provoking. It provides insight into how others have dealt well or not-so-well with the need to display multivariable information clearly and crisply via a two-dimensional image, even in the pre-computer age. The basic guidelines for a good chart are the same for both eras, but there are some differences as well.

Are there graphs or charts you recall that gave you a clear sense of the “big picture” and to which you still refer? Are there any that caused you to say “aha — now I get it” about a complicated or multidimensional topic?

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The post Good Graphics Clarify Technical Attributes of Power Process appeared first on EETimes.

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